Big Ass Fan Co.’s Powerfoil D high volume, low speed (HVLS) fan features a direct drive. It has an airfoil system with six aluminum airfoils and winglets, and comes in diameters of 8 feet to 24 feet. The Powerfoil D HVLS fan can be used inside or outside. There are 240-volt and 480-volt models available. They also have static tubes for an optional LED kit, occupancy sensor and other attachments.